Darwin’s Duomo and Gould’s Pinnacle

April 2002

A review of Stephen Jay Gould’s The Structure of Evolutionary Theory.

We live in the Age of Science. Scientism is our worldview, our mythic story about who we are, where we came from, and where we are going. As such, scientists are our preeminent storytellers, the mythmakers of our epoch. Prominent among them are such cosmologists and evolutionary theorists as Stephen Hawking and Carl Sagan, Edward O. Wilson and Richard Dawkins, whose books are read by professionals and the public alike, with spectacular advances and (hopefully) matching sales that reflect the rise of a scientistic literati, where it is now chic to have read (or at least to have on your coffee table) their works.

Stephen Jay Gould has been a highly successful product and producer of this salubrious arrangement between scientists, agents, publishers, and readers. Stretching to 1,433 pages and weighing in at 5.5 pounds, Gould’s magisterial The Structure of Evolutionary Theory is destined to go down in the annals of this genre alongside the works of Galileo, Darwin, Huxley, Freud, Mayr, and others who write for the ages, as changing forever both colleagues and cultures. His critics — and there are plenty — may weep and gnash their teeth at such an assessment, but they ignore Gould at their — and our — peril. This man has something important to say about the preeminent origin myth of our age — evolutionary theory — and he has said it in this magnificent work.

The Structure of Evolutionary Theory is an elegant blend of science and history that revises both Darwin’s original 19th-century theory and the neo-Darwinian synthesis of the mid-20th century. Over the past four decades — during which he penned over 500 scientific papers, 300 essays, and 21 other books — Gould has systematically built upon Darwin’s cathedral, an apt metaphor as his tome begins with an architectural analysis of the Duomo (Cathedral) of Milan, showing how the original 14th century foundational structure was appended over the centuries with spires and pinnacles, such that we can legitimately say a core structure remains intact while the finished building represents a far richer compendium of historical additions. Gould’s mission is not to raze the Darwinian Gothic structure, or to tear down the neo-Darwinian Baroque facades, but to revise, refine, reinforce, and reconstruct those portions of Darwin’s Duomo that have begun to crumble under the weathering effects of a century and a half of scientific research.

The foundation of Darwin’s Duomo rests upon three theoretical pillars (or, in the visual metaphor that graces the cover of this handsomely-produced volume, a three-pronged fossil coral, whose foundational trunk gives rise to three branches). All three pillars are needed to prevent the theory from toppling over, which it might do, says Gould, unless necessary retrofittings and revisions are implemented. There are three theoretical pillars.

Agency, or the level at which evolutionary change occurs. For Darwin, it is individual organisms alone that are being selected for or against. Gould proposes a multi-tiered theory of evolution where change (and selection) occurs at a number of different levels — genes, cell-lineages, organisms, demes, species, and clades.

Efficacy, or the mechanism of evolutionary change. For Darwin it was natural selection (and its handmaiden sexual selection) alone that drives organisms to evolve. Gould does not deny the power of natural selection, but wishes to emphasize that in the three billion-year history of the earth’s rich panoply of life, there is so much more to the story. On top of the substratum of microevolution Gould adds macroevolution — long-term changes caused by mass extinctions and other large-scale forces of change. To the bottom floor of adaptationism Gould attaches exaptationism — structures subsumed for later uses and whose original adaptive purposes are now lost to history.

Scope, or the range of effects wrought by natural selection. For Darwin, gradual and systematic change extrapolated over geological expanses of time is all that is needed to account for life’s diversity. For Gould, slow and steady sometimes wins the race, but more often than not life is punctuated with catastrophic contingencies that fall in the realm of unique historical narratives rather than predictable natural laws. History, not physics, should be evolutionary theory’s model of science.

Revisions to these three branches (while the main Darwinian trunk retains its theoretical power), says Gould, produces a “distinct theoretical architecture, offering renewed pride in Darwin’s vision and in the power of persistent critiques — a reconstitution and an improvement.” Some of those critiques, however, have been aimed not at Darwin’s Duomo, but at Gould’s Pinnacles. To his credit, Gould unhesitatingly allows his critics to speak, but the price they pay is facing the buzz saw of his rhetorical brilliance (and literary erudition), as in this maximally insulting cut of one critic when he quotes Schiller: “Mit Dummheit kämpfen die Götter selbst vergebens” (“even the gods cannot fight with stupidity”).

One persistent misunderstanding about Gould’s remodeling of Darwin’ Duomo stems from what I call (in my book The Borderlands of Science) the “paradigm paradox.” How can the paradigms of Darwinism, neo-Darwinism, and Gouldian Darwinism co-exist peacefully? Doesn’t one paradigm displace another in a way that makes them incompatable? No. Paradigms can build upon one another and cohabit the same scientific niche. Just as the Newtonian paradigm has been reconstituted to include the paradigms of relativity and quantum mechanics, the overarching Darwinian paradigm has been improved by, for example, the subsidiary punctuated equilibrium paradigm, that constitutes an improved reading of the herky-jerky fossil record whose numerous gaps so embarrassed Darwin. (The gaps, say Gould and his co-theorist Niles Eldredge, represent data of a speciational process that happens so rapidly that few “transitional” fossils are left in the historical record.) Both Darwinian gradualism and Gouldian punctuationism constitute paradigm shifts, with each filling a theoretical ecosystem that allows disperate forms of data to be properly interpreted.

Think of species not as billiard balls being knocked about the table of nature willy nilly, but as polyhedrons, or multi-faceted structures (think of an eight-sided die) that sit on a side until nudged by a potent force, and whose internal properties, Gould writes, “‘push back’ against external selection, thereby rendering evolution as a dialectic of inside and outside.” Without discounting the outside, Gould wants us to look again inward (as so many evolutionary theorists did in Darwin’s own day), where the restricting channels of both nature and history direct the selective forces in particular directions. Copious examples and eye-blurring data from numerous fields flesh out the scientific portions of this book, which critics and students alike will have to address if they want to take Gould seriously, either for or against.

Most of the theoretical themata that Gould presents (theory–data, time’s arrow — time’s cycle, adaptationism–nonadaptationism, punctuationism–gradualism, contingency–necessity) have been played out on the historical stage before, and therefore much of The Structure of Evolutionary Theory resurrects the thoughts and ideas of the great evolutionary theorists of the past two centuries. Gould may have an ego to match the Brobdingnagian proportions of this book, but he generously offers credit to the founding fathers of the field and lovingly brings their ideas back to life. Here we see Gould the humanistic historian, living up to the assessment made by the eminent science historian Ronald Numbers when he remarked to me: “I can’t say much about Gould’s strengths as a scientist, but for a long time I’ve regarded him as the second most influential historian of science (next to Thomas Kuhn).”

So, even if you disagree with Gould’s science, his historiography is stellar, although a modicum of effort will be required of readers as Gould does have a tendency to lard his narrative with 19th-century style paragraph-length sentences (analogous, he likes to say, to the “riffing” of Jazz musicians). But for those who enjoy the music — professionals and public alike — The Structure of Evolutionary Theory will leave a lasting imprint (literally and figuratively) on all who dare to take the challenge.

(Harvard University Press, 2002, ISBN 0674006135) This review was originally published in Washington Post Book World.